First, this is a FREE game, and you should totally play it, online multiplayer, first person shooter, which I like a lot, you get to use different powers with your 3 different characters, you level up as well as upgrade armor, weapons, your ghost etc. There are challenges, tough ones that you could do alone, but it's also fun to play with other people in the multiplayer campaigns.
The graphics are crazy! It looks so cool, and the sound quality is great as well, you should give it a try, if you don't like it, it was worth the try. But if you do, the expansions cost money but they are very cool to play alone or in company.